The present invention relates to a semiconductor storage device and, more particularly, to a technology effective especially if used in a static RAM (i.e., Random Access Memory) which has a multi-bit structure and which is packaged as a speech pass memory or control memory in a digital switch integrated circuit of a time sharing digital converter.
Recently, digital switch integrated circuits have been developed which form the time switches of the time sharing digital converters such as found in ISDN (i.e., Integrated Service Digital Network). These digital switch integrated circuits have packaged therein multi-bit static RAMs to be used as the speech pass memories or control memories.
Such digital switch integrated circuits having the static RAMs packaged therein is disclosed, for example, on pp. 290 to 291 and 431 of "ISSCC Digest of Technical Papers" dated on Feb. 27, 1987. On the other hand, the array dividing system of the static RAM is disclosed, for example, in Japanese Patent Laid-Open No. 211393/1983 (i.e., Japanese Patent Publication No. 28516/1987) and Japanese Patent Laid-Open No. 72699/1984.